1. Field of the Invention
The present invention relates to a chair adjustment mechanism and, more particularly, to a mechanism which can conveniently be operated to selectively adjust a seat, back or arm relative to a chair support structure, the mechanism being simple, inexpensive and reliable.
2. Description of Related Art
Many forms of back adjustment mechanisms are known, particularly for chairs used in office environments. Often, it is desirable to adjust the vertical height of a chair back for the comfort of the user as the user is engaged in various office-related tasks. The same is true of a chair seat and a chair arm. One such chair back adjustment mechanism, for example, which is well-known in the art, is a simple slide mechanism which moves vertically on a chair back support, usually comprising one or two tubes, with a manually tightened knob that can lock the back in a predetermined vertical position relative to the chair seat.
While such chair adjustment mechanisms have proved to be reliable and economically manufacturable to produce, it is desirable to provide an improved mechanism which is cost-effective to produce and provides increased convenience to the chair user.
The difficulties encountered with previous devices have been overcome by the present invention. What is described here is a chair adjustment mechanism comprising a base adapted to be attached to a chair in a fixed position, a slide connected to the base and movable between a retracted position and a fully extended position in relation to the base, the slide being guided by the base, a space formed between the base and the slide, a series of ramps connected to extend between the base and the slide in the space for lockingly positioning the slide in intermediate positions between the retracted position and the fully extended position, a spring device mounted between the base and the slide and capable of engaging the series of ramps, the spring device being flexed between two positions, a first position wherein the spring device makes selective contact with individual ramps of the series of ramps and a second position wherein the spring device is able to avoid engagement with the ramps of the series of ramps, a first high ramp operatively connected to flex the spring device from its first position to its second position, and a second high ramp operatively connected to cause the spring device to move from its second position to its first position.
There are a number of advantages, features and objects achieved with the present invention which are believed not to be available in earlier related devices. For example, one advantage is that the present invention provides a chair adjustment mechanism which is quite simple, being constructed of only three molded synthetic resin parts. Another object of the present invention is to provide a chair adjustment mechanism that is relatively inexpensive. A further advantage of the present invention is to provide a chair adjustment mechanism which is reliable. Another feature of the present invention is to provide a chair adjustment mechanism which may be used to adjust the back of a chair, the seat of a chair or the arms of a chair.
A more complete understanding of the present invention and other objects, advantages and features thereof will be gained from a consideration of the following description of a preferred embodiment read in conjunction with the accompanying drawing provided herein. The preferred embodiment represents an example of the invention which is described here in compliance with Title 35 U.S.C. section 112 (first paragraph), but the invention itself is defined by the attached claims.